Ballista

Onager

The onager was a special kind of catapult. Used during the post-classical era, its name came from the onager, or wild donkey. This reason was because the machine's recoil action was similar to that of the wild ass. The onager was originally meant to be a cheaper and simpler version of the ballista. The onager was first mentioned by name by military engineer Ammianus Marcellinus, who worked for Roman emperor Trajan. However, according to author Alan Wilkins, the onager was mentioned around 200 BC by Philon of Byzantium in his book Poliorketika. In it, Philon write the following:

"You must try smash through the roofs of the siege-sheds by releasing very large stones from machines and projecting beams, and by shooting from above by one-talent and one-arm stone throwers."

Onagers were mainly used for besieging civilian settlements or military forts. The onager worked thanks to torsional pressure. The pressure came from twisted rope or animals tendons, which stored enough energy to fling ammo to its unfortunate target. The ammunition used was large stones; one of the onager's weaknesses was that it couldn't fire anything smaller than that. Sometimes special clay balls filled with combustible materials were used as ammunition instead of stones; these balls would explode and cause fires once they reached their targets. Some enterprising generals sometimes had the stones covered with oil and set alight before flinging them at the enemy, as seen in many Hollywood films. The onager was less accurate than the ballista; but it was also more powerful, making it perfectly designed for burning and breaking down gates and walls during siege warfare.

The onager was set on a horizontal frame. On the front of the frame a solid wooden vertical frame was tightly fixed. Through this frame went an axle, which went through a rope knot and ended with a stout spoke. A hook was then usually embedded in the spoke; a sling was then hung on the hook. the reason the Romans used a sling instead of a spoon or bowl for their catapults was that a sling is far more efficient in catapults than bowls or spoons. Stones were then placed in the sling and fired at the enemy. In battle, soldiers would pull the spoke down against the spring tension with the help of a windlass. The spoke would then be suddenly released (similar to a staff-sling), hitting the vertical frame's crosspiece and flinging the stone at its target. The spoke would be caught by padding attached to the crosspiece and then be winched back into position, ready for more action. Ammianus Marcellinus, a Roman historian from the 3rd century A.D, described it in this way:

The onager's framework is made out of two beams from oak, which curve into humps. In the middle they have quite large holes in them, in which strong sinew ropes are stretched and twisted. A long arm is then inserted between the bundle of rope, at its end it has a pin and a pouch. It strikes on a huge buffer with a sack stuffed with fine chaff and secured by tight binding. When it comes to combat, a round stone (often clay balls with combustible substance in them, which explode on impact and burst into flames) is put in the pouch and the arm is winched down. Then, the master artilleryman strikes the pin with a hammer, and with a big blow, the stone is launched towards its target.

When the Roman Empire fell apart, the onager was retired. But around 1200 A.D, a similar machine called the mangonel appeared in medieval Europe. Although less powerful than the onager, it used a fixed bowl instead of a sling, which meant it could fire a large variety of items, and not just large rocks. Some people, however, think that the drawings of mangonels we see in medieval manuscripts were intentionally sabotaged and that catapults still use slings during the Early and High Middle Ages. The reason for this was that catapults were considered to be a state-of -the-art weapon. As a result, the exact details on its construction and operation were a closely guarded secret. But no one knows this for sure, so you're free to make up your own mind.

Scorpio

The scorpio (also known as a triggerfish) was a small catapult-like weapon which was fired by one man. It was basically a early version of the crossbow. The scorpio was probably first invented by the ancient Greeks, who called it a "catapult with bolts". The Romans later took a fancy to the artiley piece and began to use it extensively in their armies. ﻿The﻿scorpio was actually more of a sniper weapon than a siege weapon.It fired bolts through a system of torsion springs. But the scorpio had a downside; it was extremely complicated to make and to maintain, especially the torsion springs. In fact the Latin word for "torsion spring" was tormenta!. If there was any change in temperature or moisture in an area of battle, the scorpios would be affected.

During the period of the Republic and early empire, each Roman legion had 60 scorpios, or one per century. The scorpio was often place on top of a hill or other high ground. From there, it would shoot at the surrounding enemy. Its centuries would surround the sides of the hill and protect the scorpio. The scorpio were used there for two things: parabolic shooting and precision shooting. During parabolic shooting, the scorpio could hit a target up to 400 meters away at a rate of 3 or 4 bolts per minute (in other words, 60 scorpios could fire up to 240 bolts per minute at the enemy!). During precision shooting, the rate was quite a bit lower and the firing range was reduced to 100 meters. But the accuracy of the shots were far greater. Skilled scorpio controllers could pick off soldiers from the top of walls. Julius Caesar used precision shooting with devastating results at the Siege of Avaricum. The bolts used for scorpios were heavy enough to penetrate shields and most armor. Thus most enemies hit by a scorpio's bolt would at least be wounded, if not killed. It's no wonder that Rome's enemies feared the scorpio so much.

After the Roman Empire had fallen, some countries still used the scorpio. But by the High Middle Ages, most European countries had abandoned the scorpio, with the exception of the Byzantine Empire. The scorpio, however, made a surprise comeback during the First Crusade in the form of a new type of catapult. This new catapult fired stone spheres thanks to a system of counterweights and slings. Advances in metallurgy also resulted in giant crossbows which were similar to the scorpio.